PHOTO: Britain's PrinceWilliam , the DukeofCambridge adjusts his helmet as he prepares to board an East Anglian Air Ambulance (EAAA), to begin his new job, at Cambridge Airport, Cambridge, in England,July 13, 2015.

PHOTO: In this handout photo provided by Government House NZ, PrinceWilliam , DukeofCambridge , Catherine, Duchess of Cambridge and Prince George attend Plunkett's Parent's Group at Government House on April 9, 2014 in Wellington, New Zealand.

PHOTO: Britain's PrinceWilliam and Kate, Duchess of Cambridge and their newborn baby princess, pose for the media as they leave St. Mary's Hospital's exclusive Lindo Wing, London, Saturday, May 2, 2015.

PHOTO: Britain's PrinceWilliam and Kate, Duchess of Cambridge and their newborn baby princess, pose for the media as they leave St. Mary's Hospital's exclusive Lindo Wing, London, Saturday, May 2, 2015.